A piston-and-cylinder device contains 10 kmol of n-pentane at -35.5 C and 100 bar. Slowly the piston is moved until the vapor pressure of n-pentane is reached, and then further moved until 5 kmol of the n-pentane is evaporated. This complete process takes place at the constant temperature of -35.5 C. Assume n-pentane can be described by the Peng-Robinson equation of state.
a) What is the volume change for the process?
b)How much heat must be supplied for the process to be isothermal?